I have a lookup routine that I created and compiled into a DLL. I am using this in another program as such:
Dim frm As frmSupplierLookup
frm = New frmSupplierLookup("", Database, Company)
frm.Show()
This works fine.
What I need to be able to do is have the "frmSupplierLookup" part be a variable. For instance, sometimes it may need to be "frmCustomerLookup", which is another form in my DLL.
This will be stored in a database and be user-defined and could change in the future. So using a Select/Case statement or similar routine will not work. It must truly be generic.
How can I do this?
Thanks,
Chris
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That wasn't enough to outright help me. I searched on Activator.CreateInstance and found some good examples. However, I am having trouble with the GetType on the class.
When I put the following in the Watch window, it returns Nothing.
Type.GetType("CommonLookup
What might I be doing wrong?
the problem is with the string you are passing to Type.GetType.
Assuming you are building w/ Studio .Net, and have neither edited Assembly.info nor changed the project's root namespace, you should be able to run the following.
Namespace MyTestNamespace
Public Class MyTestClass
Public Function MyTestFunction() As String
Return "Hello World"
End Function
End Class
End Namespace
Namespace MainNamespace
Public Class MainClass
Shared Sub Main()
Const TYPE_STRING As String = "WindowsApplication1.MyTes
Dim myType As System.Type = Type.GetType(TYPE_STRING, True, True)
MsgBox(DirectCast(Activato
End Sub
End Class
End Namespace
Thanks. I'm really close now. The only remaining problem seems to be how to pass in the parameters. I did some googling and thought I had it but it's giving an error.
Here is my "hard-coded" code that works fine:
Dim frm As frmSupplierLookup
frm = New frmSupplierLookup("", Database, Company)
frm.Show()
Here is my new code:
Dim myType As System.Type = Type.GetType("CommonLookup
"CommonLookupRoutines, Version=1.0, Culture=neutral, PublicKeyToken=null", True, True)
Dim frm As Form = DirectCast(Activator.Creat
Nothing, New [Object]() {"", Database, Company}), Form)
frm.Show()
When I run this, I get the error message "Constructor on type 'CommonLookupRoutines.frmS
The constructor is there (as witnessed by the fact that the original code above works). I'm guessing that I'm not properly passing the parameters but I guess I'm not certain.
Nevermind, I figured it out by using a different overload. The following code works:
Dim myType As System.Type = Type.GetType("CommonLookup
"CommonLookupRoutines, Version=1.0, Culture=neutral, PublicKeyToken=null", True, True)
Dim frm As Form = DirectCast(Activator.Creat
frm.Show()
Thanks for your help.
Business Accounts
Answer for Membership
by: bisonfur37Posted on 2006-04-13 at 14:10:06ID: 16449524
I would store the class name in a config file (e.g. App.Config) and use the Activator.CreateInstance method to generate the object at runtime.
Also, check out the Factory / Abstract Factory Design Patterns (http://www.dofactory.com/